Evidence review
What to inspect before changing anything
Start with the delivered website and the real user journey. Record the current state so the team can distinguish an observed problem from an assumption and compare the same surface after deployment.
- 01Compare intrinsic and rendered dimensions
- 02Find oversized formats and missing dimensions
- 03Identify the true largest image
Implementation
A practical improvement plan
Make the smallest coherent change that solves the observed problem. Keep normal code review, accessibility, security and product checks in the loop instead of optimizing for the scan alone.
- 01Generate responsive variants
- 02Choose appropriate modern formats
- 03Set dimensions, loading and fetch priority deliberately
Verification
How to verify the result
Verification should test the intended outcome and the most likely regression. Use the production delivery path whenever headers, caching, rendering or third-party services affect the result.
- 01Test DPR and viewport variants
- 02Inspect transferred bytes and visual quality
- 03Measure layout stability and hero timing
Common pitfall
A shortcut to avoid
Compressing one giant source image does not replace serving an appropriately sized variant.
Further reading
Primary guidance and references
These sources provide standards, security guidance or the interpretation framework used to keep this guide bounded. Product-specific implementation still requires review in the actual codebase.